1. Field of the Invention
The present invention relates to a blood sugar measuring system. More particularly, the present invention relates to a noninvasive in vivo measuring system and a noninvasive in vivo measuring method which can accurately measure blood sugar by correcting influence of Hemoglobin (Hb) concentration.
2. Description of Related Art
Improved lifestyles have increased adult diseases. This also has increased peoples' concerns about their health.
Diabetes is one type of adult disease and the number of diabetics is also significantly rising.
Diabetes is a medical condition in which someone has too much glucose, that is, blood sugar in their blood because of the lack of insulin in their body and discharges the glucose along with the urine. Accordingly, diabetics need to test their blood sugar about six times a day in order to adjust the blood sugar in their blood. Also, blood sugar is one of the most important components informing a person of their state of health. In the case of a normal state, the blood sugar is maintained between 70 and 110 mg/dl (mg per 100 cm3). After meals, the blood sugar is maintained at less than 180 mg/dl. Also, even in the case of an empty stomach, the blood sugar is maintained at more than 60 mg/dl. However, when the blood sugar rises up to more than a normal state, a person may become dehydrated because of frequent urine, etc. When the blood sugar falls below a normal state, a person may have a feeling of uneasiness, vertigo, etc. Also, this may slow brain activities and if it gets more serious, brain cells may be damaged and consequently, a person may fall into a coma or die.
In a conventional blood sugar measuring method, an invasive method, that is a user invasively draws blood from a body and measures blood sugar concentration via blood sugar measuring instrument using an enzymatic method, is frequently used. In the invasive method, the user draws blood, the drawn blood reacts to a diagnostic reagent, and the blood is diagnosed using a clinical analyzer or a color change of a strip, having been reacted to the diagnostic reagent.
However, the conventional invasive blood sugar measuring method may inflict pain upon a diabetic patient due to a procedure of drawing blood, and also the diabetic patient may become infected with another disease due to repeated operations of drawing blood. Also, the conventional invasive blood sugar measuring method has disadvantages, in that constant monitoring is impossible and coping with an emergency situation is not simple since it requires time to draw blood. Also, the diabetic patient may incur many expenses, and waste may occur since a great deal of strips and diagnostic reagents are used, and accordingly, environmental pollution may occur due to the waste in the conventional invasive blood sugar measuring method.
To control blood sugar for the diabetic patient or to medically examine a healthy person, a technique which can measure blood sugar concentration without drawing blood and without the strips and diagnostic reagents is required. Accordingly, a noninvasive blood sugar measuring method enhancing a user's convenience has been developed and used for a limited number of users.
As illustrated in FIG. 1, in a blood sugar measuring method via a tissue modulation, one noninvasive blood sugar measuring method, when a laser which is irradiated on a finger is reflected, Raman-fluorescence spectra with respect to the reflected laser analysis is used. A phenomenon in which each component in blood has a unique Raman wavelength, and thus changes spectrum, is used.
In the Raman-fluorescence method, a blood sugar level is measured by analyzing Raman spectra, being scattered in response to a glucose component in blood and occurring in a corresponding wavelength, among fluorescence spectra of the reflected laser. This is disclosed in the U.S. Pat. No. 6,289,230.
However, the blood sugar level may not be regularly measured via the above tissue modulation in the conventional Raman-fluorescence method since the Raman spectra in response to the glucose component are affected by the other components in the blood. Specifically, as illustrated in FIG. 2, the blood sugar level is randomly shown depending on an amount of the Hb in blood.